jenkins: speed up msi/git repo creation

Currently the MSI and git repo creation part of the build is done on the network published kit. They time taken may be due to I/O on this network share. This ticket should look to:

- deploy to a local deployment area on the build server
- create the msi and kit there
- publish this to central area

A later refinement may be to move the "publish to central area" task to another service, either spawned from Jenkins or running in the background. This would speed up build turnaround, but mean that a "successful completed build" didn't mean the distribution had (yet) copied successfully. Maybe the final copy is a delay we can handle? It did get very slow at one point, but may be better now.